The majority of seroepidemiologic studies conducted on HIVs in West Africa have focused on adult sentinel population groups; children have been infrequently included in such studies. The risk factors for infection, clinical manifestations, and natural history of HIV-2 infection in pediatric populations are currently poorly understood. Our ongoing multicentric natural history studies of female prostitutes provides the a means of evaluating children at risk for infection. Data from studies on perinatally acquired HIV-1 infection in the US suggest that a significant proportion of infants will survive past 2 years of age. The natural history of HIV infection in such older age children may provide important information critical to our understanding of HIV pathogenesis. SPECIFIC AIMS: (1) To determine the seroprevalence of HIV-2 in "high risk" children. The study will include children (<12 yrs) whose mothers are prostitutes of known serostatus currently enrolled in the natural history study (Project 2). (2) To determine risk factors associated with HIV infection in such children. These will include but not be limited to risks due to perinatal or postnatal contact with an HIV positive mother, history of transfusion, multiple injections and various cultural practices. (3) To determine the health status of HIV-2 positive children compared to HIV negative comparison children. (4) Seropositive children and comparison negatives identified in the cross- sectional study will be enrolled in a prospective natural history study to characterize clinico-immunologic and virologic parameters of HIV-2 progression.